1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display with reduced crosstalk.
2. Description of the Related Art
Liquid crystal display (LCD) is a commonly used flat panel display. Owing to dielectric anisotropy and conductive anisotropy of liquid crystal molecules, molecular orientation of liquid crystals can be shifted under an external electronic field, such that various optical effects are produced.
A LCD panel is generally made up of two substrates, with a certain gap preserved therebetween, and a liquid crystal layer filled within the gap. Respective electrodes are formed on the two substrates, respectively, to control the orientation and oriental shift of liquid crystal molecules.
A TFT (thin film transistor) LCD panel is generally made up of a TFT array substrate and a color filter substrate. The detailed structures are described as follows.
FIG. 1 is a top view showing a conventional TFT array substrate. FIG. 2 is a cross-section taken at the line I—I in FIG. 1. In the manufacture of TFT array substrate, an insulating substrate 101, made of, for example, glass or quartz, is provided. A gate electrode 108 and an insulating layer 107 (not shown in FIG. 1) are then formed sequentially on the insulating substrate 101. Then, a channel layer 106 is formed on the insulating layer 107, and a source electrode 102 and drain electrode 103 are formed on the channel layer 106, respectively. Afterward, signal lines 104 and pixel electrodes 105 are formed on the insulating layer 107, electrically coupling to the source electrode 102 and drain electrode 103, respectively.
FIG. 3 is a cross-section taken at the line II—II in FIG. 1, showing the cross-section of the signal line 104.
FIG. 4 illustrates the structure of the color filter substrate. The color filter substrate includes a glass substrate 201, a black matrix (BM) 202 for anti-reflection, color-filtering units of red 203, green 204, and blue 205, and a sputtered pixel electrode layer 206 as a corresponding electrode to the pixel electrode 105 of TFT array substrate. The shapes, sizes, colors, and arrangements of the color-filtering units are adjustable according to requirements. The pixel electrode layer 206 is a transparent conductive layer of, for example, indium tin oxide layer.
After the separate manufacture of the TFT array substrate and color filter substrate, the two substrates are then aligned and joined with a gap therebetween, and liquid crystal is filled into the gap to form the liquid crystal layer 3, thereby completeing the TFT panel fabrication.
FIG. 5 is a cross-section of the TFT panel taken at the line II—II in FIG. 1.
Due to the full coverage of pixel electrode layer 206 on the upper substrate 201, the pixel electrode 206 is formed against the signal lines 104 at the same time. The pixel electrode layer 206 and signal lines 104 are made of metal. Two layers of metal with dielectric material, i.e. the liquid crystal layer 3, inserted therebetween, result in capacitor effect, which weakens the signals, produces crosstalk, deteriorating display quality and affecting yield. Moreover, crosstalk becomes more serious in larger display panels.